This invention relates generally to air conditioning systems and, more particularly, to an economizer sliding door mechanism for selectively opening the respective return air and outdoor air inlet openings thereof.
A packaged rooftop air conditioning unit typically includes indoor and outdoor sections, with the indoor section having a fan for drawing the air from the enclosure by way of a return air duct and causing it to be passed over the evaporator coil to be cooled, after which it is recirculated back to the enclosure. In order to take advantage of the cooler outdoor air during low temperature ambient conditions, an economizer is provided to draw the cooler outdoor air into the evaporator. Thus, the air passing through the evaporator may be a mixture of return air and outdoor air, with the respective quantities of each being controlled by way of a damper system.
One such economizer assembly is shown in U.S. Pat. No. 4,478,056 issued on Oct. 23 1984 and assigned to the assignee of the selectively vary the openings for the admission of outdoor air, but little, if any, control is provided for varying the opening for admission of the return air flow to the evaporator. Further, the sliding movement and positive positioning control of the door is difficult to maintain with the pivoting drive rod arrangement as provided. Another disadvantage of that system which is shown in a down discharge (i.e. return air flowing upwardly from the bottom) system, is that it is not easily adaptable to a side discharge system. That is, it would be necessary to have a different economizer for use in a side discharge system, thereby increasing the inventory requirements and complicating the assembly process.
It is therefore an object of the present invention to provide a rooftop air conditioner with an improved economizer structure.
Another object of the present invention is the provision for an economizer structure which can be selectively controlled to vary the air flow to the evaporator, both from the outdoor air inlet and the return air inlet.
Yet another object of the present invention is the provision for an improved drive mechanism for the sliding door of an economizer apparatus.
Still another object of the present invention is the provision in a rooftop air conditioning unit for an economizer which can be installed in either a down-discharge or a side-discharge unit.
Yet another object of the present invention is the provision for a rooftop air conditioner economizer structure which is economical to manufacture and effective in use.
These objects and other features and advantages become more readily apparent upon reference to the following description when taken in conjunction with the appended drawings.